The present invention relates to a rotary compressor constituted by housing a driving element and a rotary compression mechanism section driven by the driving element in an airtight container, and a car air conditioner and a heat pump type water heater using the rotary compressor.
This type of rotary compressor has heretofore been, for example, an internal intermediate pressure type multistage (two-stage) compression system rotary compressor including first and second rotary compression elements, and the compressor is constituted of a driving element and a rotary compression mechanism section driven by the driving element in an airtight container.
Moreover, a refrigerant gas is drawn in a cylinder on the side of a low pressure chamber via a suction port of the first rotary compression element, compressed by an operation of a roller and a vane to obtain an intermediate pressure, and discharged into the airtight container from the side of a high pressure chamber of the cylinder via a discharge port and a discharge noise silencing chamber. Moreover, the refrigerant gas having the intermediate pressure in the airtight container is drawn in the cylinder on the side of the low pressure chamber from a suction port of the second rotary compression element, compressed by the operation of the roller and vane in a second stage to constitute a high-temperature/pressure refrigerant gas, and discharged to the outside of the compressor from the side of the high pressure chamber via the discharge port and discharge noise silencing chamber.
Moreover, a bottom portion in the airtight container is constituted as an oil reservoir, and oil is pumped up from the oil reservoir by an oil pump (oil supply means) attached to one end (lower end) of a rotation shaft, and supplied to a sliding portion of the rotary compression mechanism section to lubricate and seal the portion (see, for example, Japanese Patent No. 2507047, and Japanese Patent Application Laid-Open Nos. 2-294587, 2000-105004, 2000-105005, 2003-74997, and 10-141270).
However, the oil mixed in the refrigerant gas compressed by the first rotary compression element as described above is discharged into the airtight container, and separated from the refrigerant gas to a certain degree in the process of movement in a space in the airtight container. However, the oil mixed in the refrigerant gas compressed by the second rotary compression element is discharged as such to the outside of the compressor together with the refrigerant gas.
Therefore, there has been a problem that the oil in the oil reservoir runs short and that a sliding performance or sealing property lowers. There has also been a possibility that a trouble is caused in refrigerant circulation in a refrigerant circuit, or the refrigerant circuit is adversely affected otherwise by the oil discharged to the outside of the compressor.
Moreover, an oil separator is connected to a piping outside the airtight container to separate the oil from the discharged refrigerant gas, and the oil is devised to be returned to the compressor in this manner, but there has been a problem that an installation space enlarges.